Tidal Locking plus Zombies
Much higher stopping power. Can fire much heavier slugs. Because iron is heavier than lead, coil guns get their power by weight and size. Unlike gunpowder guns, coil guns can be adjusted on the fly and with a range-finder, for either maximum penetration or maximum damage. Slugs are and shorter and fatter than gunpowder bullets. They are quieter with no explosion (as quiet as a suppressed bullet) but they do still break the sound barrier. Have a greater effective range than gunpowder.
Batteries and large and heavy, not as rapid fire. Tends to be built with smaller ammo cap. Can be heavier as a whole.
Rounds must be ferrous in nature, in part or in whole. Must be recharged, or it will slowly charge over time.